The present invention relates to a method of extracting castings from moulds in the manner set forth in the preamble of claim 1.
Previous methods of the kind referred to above have normally been based upon the mould being smashed in a more or less rough fashion, such as being tumbled in a drum or dropped onto a vibrating conveyor.
Especially in the case of aluminium castings, this rough treatment of the mould may damage the castings. Attempts have been made to xe2x80x9csavexe2x80x9d aluminium castings by manually gripping them before they hit the conveyor, butxe2x80x94as will readily be appreciated by persons skilled in the foundry tradexe2x80x94such manual work is both strenuous and monotonous, as well as unhealthy due to the air in the extraction station being heavily dust-laden.
Attempts have also been made by using a robot with gripper arms, making the latter penetrate through the main body of each mould to engage the casting or castings. This method is costly, as a robot with ample xe2x80x9cmuscle powerxe2x80x9d is required. Further, this method is not suitable for extracting multiple castings, because the latter will offer a too high resistance to the penetration. Still further, the gripper arms must not be too thick, calling for a compromise between mechanical strength and penetrating ability.
It is the object of the present invention to provide a method of the kind referred to initially, with which it is possible to extract the castings from the moulds using less costly equipment and with reduced risk of damage to frail castings, and this object is achieved by proceeding in the manner set forth in the characterizing clause of claim 1. By so doing, the castings may be extracted by moving each mould with the casting or castings so as to bring the latter into engagement with the engagement member or members referred to, and then again moving the mould in a manner causing the engagement member or members to loosen and liberate the casting or castings from the mould. In the simplest manner, this could be achieved by means of a hook or hooks not having to penetrate through more of the mould body than superficial portions adjacent the castings, said hook or hooks then being used to pull the castings out of the part of the casting cavity formed in the downstream face of the mould. Obviously, relatively little force is needed for these steps, for which reason a less costly robot may be used.
The present invention also relates to an automated foundry plant for carrying out the method of the invention. This plant is of the kind set forth in the preamble of claim 12, and according to the invention, it also comprises the features set forth in the characterizing clause of this claim 12.
Further embodiments of the method and the plant, the effects of whichxe2x80x94beyond what will be obvious to a skilled personxe2x80x94are explained in the following detailed part of the present description, are set forth in claims 2-11 and 13-18, respectively.